The present invention generally relates to an ultraviolet lamp assembly for killing germs or bacteria in air ventilation systems. Specifically, the present invention relates to an ultraviolet lamp including a quartz sleeve having a vented open end which results in increased or improved germicidal and bactericidal effect in systems and apparatus using ultraviolet lamps for purification or cleaning of air.
The use of ultraviolet (xe2x80x9cUVxe2x80x9d) light or radiation for its purification, germicidal and bactericidal effect is well known. UV light is commonly used to control the growth of and kill impurities in septic, water and air systems. For example, UV light or UV lamps are commonly used in heating, ventilation, and air conditioning (xe2x80x9cACxe2x80x9d or xe2x80x9cHVACxe2x80x9d) systems for purification or air cleaning purposes. UV lamps are typically installed or mounted in the air ducts of AC systems in such a manner that the UV light emitted by the lamp floods the interior of the air duct. Air flowing through that duct will be irradiated with UV radiation which will have a germicidal or bactericidal affect on the moving air thereby reducing the impurities in the air flow.
Existing air cleaning systems or devices commonly employ UV lamps similar to those shown in FIG. 1A. FIG. 1A shows a standard lamp 5 and a sealed lamp 10 with a quartz sleeve 15 built right onto the UV lamp 10. FIG. 1A also shows a typical external quartz sleeve 20 that is often used to house standard UV lamps 5. The quartz sleeve 20 can be used, for example, to physically separate the standard UV lamp 5 from a contaminated medium, i.e. the liquid or air to be cleaned, that is being irradiated with UV radiation.
Existing air cleaning devices typically employ the standard or sealed UV lamps 5 and 10 alone or in combination with a closed end outer quartz sleeve 20. A drawback of the UV lamps 5 and 10 used in existing cleaning devices or assemblies is that the UV lamps 5 and 10 typically have diminished UV radiation output intensity over time that results in reduced germicidal and bactericidal affect of the UV lamp cleaning device. For example, FIG. 1B illustrates a typical plot of a standard UV lamp output intensity 50 over time for a typical UV lamp 5 in still air. FIG. 1B indicates that the UV lamp output 50 typically reaches its maximum rated output intensity 53, at about 56.1 mWatts/cm2, after the first few minutes of operation after an initial heat up period of the UV lamp 5. The UV lamp output 50 then typically decreases over time to a generally steady lamp intensity output 56 of about 44.6 mWatts/cm2 as the lamp continues to operate. The steady state output 56 is about 20% less that the maximum output 53 obtained during the first few minutes of UV lamp 5 operation. The drop in UV lamp output intensity 50 is typically due to the inconsistent and variable temperature around the UV lamp 5 that does not allow proper and uniform UV lamp 5 cooling. The diminished UV lamp output 50 shown in FIG. 1B is even more pronounced when air or water is circulated around the lamp which causes a higher rate of cooling as is well know to those of skill in the art.
Moreover, inconsistent and variable temperatures present around the standard UV lamp 5 result in a cooling affect that does not allow proper and uniform UV lamp 5 cooling. In the long term, this cooling effect can adversely affect the UV lamp""s 5 germicidal or bactericidal effect by causing the inside of the lamp to blacken or darken which in turn causes or results in a reduced UV lamp output intensity level 50. FIG. 1C graphically illustrates the loss of UV lamp output intensity 50 throughout the effective life of the UV lamp 5 as a result of the cooling effect. FIG. 1C indicates that throughout the effective life of the UV lamp 5, the percent of 100 hour rated output of the UV lamp 5 experiences a fairly steep decrease from about 100% when first operated to about 80% at about 1300-1325 hours of UV lamp 5 operation, and to about 65% at about 9000 hours of UV lamp 5 operation. The UV lamp output intensity 50 loss experienced throughout the life of the UV lamp 5 is another drawback of existing standard UV lamps 5.
In another typical UV lamp configuration, the UV lamp 10 is mounted inside a quartz tube as an attempt to counter act know lamp-cooling issues or problems. However, this configuration, when operated in still air, results in a larger drop in UV lamp intensity output 60 that that shown in FIG. 1B. FIG. 1D illustrates a typical plot of UV lamp output intensity 60 over time for a typical UV lamp with a quartz outer tube 10 in still air. FIG. 1D shows that the UV lamp output 60 typically reaches its maximum rated output intensity 63, at about 52.7 mWatts/cm2, after a few minutes of operation after the initial heat-up or warm-up period of the UV lamp with a quartz outer tube 10. Again, the UV lamp output 60 will typically decrease to a generally steady lamp intensity output 66 of about 34.5 mWatts/cm2 as the lamp continues to operate. In this configuration, the steady state output 66 is about 35% less that the maximum output 63 obtained during the first few minutes of UV lamp 10 operation. Thus, the quartz outer tube results in a greater loss of UV lamp output intensity 60.
There is thus a need for an improved ultraviolet UV lamp assembly having increased and/or improved UV radiation intensity output for improved germicidal and bactericidal effect in purification, sterilization, cleaning of airflow systems.
The present invention provides an improved ultraviolet lamp assembly using an ultraviolet (UV) lamp with a vented closed end quartz sleeve or tube having improved and increased UV lamp intensity output for increased germicidal and bactericidal effect. The UV lamp assembly of the present invention can be used in systems and applications with the goal to purify, sterilize, clean and sanitize a medium, object or apparatus.
The ultraviolet lamp assembly comprises a UV lamp housed in a vented closed end quartz sleeve or tube. The quartz sleeve further comprises a closed end and an open end through which the UV lamp is inserted into and secured to the tube. The open end of the quartz sleeve comprises a plurality of inlet and outlet venting slots or ports that allow the air between the UV lamp and the sleeve wall to enter and exit the quartz sleeve or tube. The UV lamp assembly also comprises a sleeve divider operatively disposed between the UV lamp and the sleeve wall that divides the interior of the sleeve into two interior compartments that allow air to circulate through the quartz sleeve. The ultraviolet lamp assembly further comprises an air displacer or fan operatively connected to at least one of the venting slots for production of air flow into and out of the quartz tube.
It is an object of the present invention to provide an ultraviolet lamp assembly that can be used in an AC or HVAC systems, and air ducts for purification and cleaning of air flowing in the AC or HVAC system and air ducts.
It is an object of the present invention to provide a UV lamp assembly with a vented closed end quartz sleeve to provide improved and constant UV radiation intensity output.
It is an object of the present invention to provide a divider in the vented closed end quartz sleeve resulting at least two compartments in the sleeve that allow air to circulate through the sleeve resulting in normalized or constant UV lamp temperature.
It is an object of the present invention to increase UV lamp life by producing more consistent and stable UV lamp temperature.
It is an object of the present invention to provide a UV lamp assembly with a vented closed end quartz sleeve and a sleeve fan that provides air flow in the sleeve in the range of about 0.5 cfm to 10 cfm when an associated sleeve fan is operating.
It is an object of the present invention to provide a UV lamp assembly with a vented closed end quartz sleeve where the UV radiation intensity output is substantially uniform and constant about 100-110 mWatts/cm2 when an associated sleeve fan is operating.
It is an object of the present invention to provide a UV lamp assembly having an effective germicidal and bactericidal affect in a wavelength bandwidth of about 240 nm to 360 nm.
It is an object of the present invention to provide an ultraviolet lamp assembly that can be used to purify air in an airflow system such as an air conditioning system in a home, hotel or building.
It is an object of the present invention to provide an ultraviolet lamp assembly that can be used to purify liquids, such as water, in a liquid purification system, such as a water treatment plant.
It is an object of the present invention to provide an ultraviolet lamp assembly that can be used to purify or sterilized objects or apparatus such as medical instruments and equipment.
The following drawings and description set forth additional advantages and benefits of the invention. More advantages and benefits will be obvious from the description and may be learned by practice of the invention.